Derwent Villages

Natural flood management interventions along the River Derwent

We are trialling a variety of Natural Flood Management techniques in the upper catchment to help slow the flow of water and retain more water on the land in periods of heavy rain. We are collecting data and evidence which will inform future work across the country.

Natural Flood Management (NFM) means using natural processes to reduce the risk of flooding and erosion.

More information about each of these interventions is below!

Leaky dams

These structures are designed to let water flow under them in regular flow conditions and only begin to work when the water levels increase during heavy rainfall.

Here, they enable water to temporarily pool behind the structure and to slowly ‘leak’ through the woody material rather than rushing down the river channel, potentially flooding peoples’ property and land.

Tree planting alongside the River Derwent

Planting trees

Trees take up water from the ground, decreasing the amount of runoff into nearby rivers and streams.

Areas of newly planted trees are often fenced off to protect them from livestock grazing. The rough vegetation in these fenced off areas acts as a great method of slowing the flow of water and it also enables fine sediment to settle out before it can enter the river.

Riverside fencing

Creating a buffer strip of rough vegetation next to a river is a great way of slowing the flow of water from the land into the river.

Water will flow much slower through an area of long, rough vegetation compared to a field of short grazed grass or bare land waiting to be planted with crops.

Moorland - hole filled with water trapping sediment

Sediment traps

Sediment traps are small depressions which are dug out to intercept rainwater flowing over the land. Water is temporarily held in these traps, before slowly draining out after the rain stops.

As the name suggests, fine sediment will settle out onto the bottom of the sediment trap before it ends up in the watercourse.